1. Technical Field
The present invention relates generally to delivery of digital content over a distributed network.
2. Description of the Related Art
It is well-known to deliver digital content (e.g., HTTP content, streaming media and applications) using an Internet content delivery network (ICDN). A content delivery network or “CDN” is a network of geographically distributed content delivery nodes that are arranged for efficient delivery of content on behalf of third party content providers. A request from a requesting end user for given content is directed to a “best” replica, where “best” usually means that the item is served to the client quickly compared to the time it would take to fetch it from the content provider origin server.
Typically, a CDN is implemented as a combination of a content delivery infrastructure, a request-routing mechanism, and a distribution infrastructure. The content delivery infrastructure usually comprises a set of “surrogate” origin servers that are located at strategic locations (e.g., Internet network access points, Internet Points of Presence, and the like) for delivering copies of content to requesting end users. The request-routing mechanism allocates servers in the content delivery infrastructure to requesting clients in a way that, for web content delivery, minimizes a given client's response time and, for streaming media delivery, provides for the highest quality. The distribution infrastructure consists of on-demand or push-based mechanisms that move content from the origin server to the surrogates. In addition, the CDN infrastructure typically includes network monitoring systems to continuously monitor the state and health of servers and the networks they are in, a network operations command center (NOCC) that monitors the state of the network on a 24×7×365 basis, a customer-facing extranet portal through which CDN customers obtain real-time and historical usage information and access to content management provisioning tools and the like, administrative and billing systems, and other CDN infrastructure and support. Some CDN service providers provide ancillary infrastructure and services such as high performance, highly-available, persistent storage, tiered distribution through cache hierarchies, edge content assembly, content targeting, and the like.
An effective CDN serves frequently accessed content from a surrogate that is optimal for a given requesting client. In a typical CDN, a single service provider operates the request-routers, the surrogates, and the content distributors. In addition, that service provider establishes business relationships with content publishers and acts on behalf of their origin server sites to provide a distributed delivery system. A well-known commercial CDN that provides web content, media streaming and application delivery is available from Akamai Technologies, Inc. of Cambridge, Mass.
Implementation, operation and management of a global distributed network—such as an Internet CDN—is a complex, costly and difficult endeavor. A large CDN may have thousands of servers operating in hundreds of disparate networks in numerous countries worldwide. Typically, the CDN service provider (a CDNSP) does not own physical support infrastructure (i.e., networks, buildings, and the like) on which the CDN servers run, nor does the CDNSP necessarily have the capability of administrating those servers that are often deployed throughout the world. Rather, the service provider must deploy and then remotely administer these services and applications as what is, in effect, a virtual network overlaid on the existing (often third party owned and controlled) physical networks and data centers.
Many network service providers desire to provide content delivery services, however, the cost of designing, installing, managing and operating a full end-to-end CDN is prohibitive.